Several experiments were carried out on directions of influence in mother-infant interaction. Seemingly responsive but incidental behaviors attributed to each mother's own 3-month-old infant were found to condition maternal verbal phrases accompanied by smiles, nonsmile facial expressions, and the display of a particular toy. These demonstrations of the infant conditioning its mother are of one mechanism whereby the infant influences its mother in the early months of its life. BIBLIOGRAPHIC REFERENCES: Gewirtz, J. L., and Boyd, E. F.: Experiments on Mother-infant Interaction Underlying Mutual Attachment Acquisition: The Infant Conditions the Mother. In Alloway, T., Pliner, P. and Krames, L. (Eds.), Attachment Behavior. New York and London: Plenum Press, 1977. Pp. 109-143. Gewirtz, J. L. and Boyd, E. F.: Mother-infant interaction and its study. In H. W. Reese (Editor), Advances in Child Development and Behavior. Vol. 11. New York and London: Academic Press, 1976. Pp. 141-163.